Stress concentration near stepped holes in plates of medium thickness

Abstract

1. The stress distribution near the hole in model No. 1 is in close agreement with the well-known theoretical distribution for narrow and thin plates [1]. The changes in stress along the plate thickness at the hole contour can be neglected. The maximum reduced stress σθ/σ θ * at the hole contour (coefficient of stress concentration) is 3.52. 2. In the case of elongated holes the maximum stress occurs at the circular portion before it joins the straight sides. The coefficient of stress concentration at this point is 3.5. The stresses then decrease and fall by 15% at the middle of the straight sides. The stresses are practically constant along the plate thickness. 3. The presence of stepped holes (models No. 2, 4) results in an increase in contour stresses at the steps and the coefficient of stress concentration reaches 4.0. The distribution of contour stresses along the plate thickness is also not uniform.